Something about Classic ID and Classic Dilbert, should you find them on the Web. The drawing are sketchier, but the humor is edgier.
Compare the king in an old strip:
Something similar happened to Dilbert. Originally, he (and the pointy-haired boss) looked like
That is, he had a longer head, an iconic curled tie, and when standing was tall with long legs. PHB was short out of proportion, not much skull. In the earliest strips, he was even sketchier. Now they look like this:
Now they are the same height, Dilbert's head has become shorter, the boss' head has become normally proportioned, the pointy hair is more stylized. And no one wears ties anymore. The strip had been trending toward cartoons over caricatures. We seldom see anymore Bob the Dinosaur that lives in his basement or even the genius garbage collector and the other outre characters that once inhabited the strip.
There is only one thing that can account for these differences: the Theory of Comic Change.